1. Field Of The Invention
This invention relates to improvements in removable core locks and particularly to a removable core lock and key assembly utilizing a unique key operated spring clip holding arrangement for controlling removability of the core.
2. Background Art
Removable core locks are well known in the art and are highly desirable in that they allow changing of locks (and keys) by merely removing the core or plug of the lock, and replacing it with another core operable by another key. The art on removable core locks is well worked as shown, for example, see U.S. Pat. Nos. 463,457, 4,484,462, 4,191,037, 4,123,926, 4,672,827, 4,761,978 4,712,400, and 4,715,201, as well as a prior patent to applicant's assignee, Medeco Security Locks Inc., U.S. Pat. No. RE 31,910.
Even though the art on removable core locks is well worked, there is still room for improvements particularly for a removable core lock that is simple to operate, inexpensive to manufacture, utilizes a movable core control key which has the same bitting as the operation key but is recognizable as a control key, and which has increased pull resistance to force if an attempt were made to "pull" the plug.